Crank-shaft.



H. L. ARNOLD.

GRANK SHAFT.

APPLICATION FILED 0GT.7, 1909. 1,024,817. Patented Apr. 30, 1912.

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Y H. L. ARNOLD.

CRANK SHAFT.

APPLICATION FILED 00127, 1909.

Patented Apr. 30, 1912.

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(iRANK-SHAFT.

Speciieation of Letters Patent.

Patented Apr. 30, 1912.

Application filed October 7, 1909. Serial No. 521,506.

To all whom vit may concern:

Be it known that I, HORACE L. ARNOLD, a citizen of the United States,residing in the borough of Brooklyn, city of New York, county of Kings,and State of New York, have invented certain new and useful Improvementsin Crank-Shafts, of which the following is a specification. 1

This invention relates to crank shafts and has for its objectto providean improved built up crank shaft and the vinterchange able parts forbuilding up the same.

In this present improvement the members of the crank shaft, that is thecrank arms, wrist pins, and end portions of the shaft, will be sointerchangeable in their character that these parts or members may betaken from stock and readily and accurately assembled in building up acrank shaft having any desirable number of crank wrists and pairs ofassociated arms disposed at any desirable angle one relative to theother. A stock postI may also be used in making repairs to replaceanother.

In the drawings accompanying and forming a part of this specification,Figure 1 is a side elevation, it being partly broken' away, andillustrates a built up crank shaft embodying my invention, wherein thereare shown two crank wrists, two pairs of crank arms, two end portionsandan intermediate bearing portion similar to the crank wrists, a portionof a connecting rod on each wrist, and a bearing supporting theintermediate bearing portion. Fig. 2 is a. longitudinal section of acrank arm, the section being taken at a plane at about right angles tothat of Fig. l, and on a larger scale. Fig. 3 shows a form of reamer tomake the eyes in the cranks. Fig. 4 is a longitudinal section throughone of the cranks. Fig. 5 is a view similar to Fig. 2, but showingunreamed eyes. Figs. 6 and 7 are end and cross sectional viewsrespectively of a form of key or binding bolt. Figs. 8 and 9respectively represent the end and the elevation of a wrist pin. Figs.10 and 11 are similar views of the end or shaft member of the crankshaft. Figs. 1Q, 13 and 14 are diagrammatic details illustrating shaftshaving respectively two, three and four wrist pins. A crank shaft builtup in accordance with the present invention will be made up ofpractically three members or their duplication, the arm, the wrist pin,which will also be used for the intermediate bearing portions of theshaft, and the end member. By reference to Fig. 1 it will be seen thatthere is a shaft built up in which there are two crank wrists,designated without preference by the reference character l, each ofwhich is carried by a pair of armsrQ, the. pairs of arms being connectedtogether byl an intermediate bearing portion 3 similar to the wristpins, and the ends of the shaft comprise members 4.

The advantageof the present improvement is that the crank shaft. aswas-before stated, -is made up ofthe duplications of but threemembers,-the arm. the shaft end, and the wrist pin, which will be madeup as interchangeable stock articles,'and used indiscriminately in theoriginal assemblage. For repairing by replacing-from stock, any

Worn or broken member of the built up shaftmay be removed and a new onesubstituted without injuring or destroying the other parts or members ofthe shaft. A shaft may be built up having any desirable number of crankwrists. In the present structure each of the members is provided with aseries of grooves and ribs 6 and 7 respectively, the grooves upon thewrist pins and shaft members being constructed and adapted for receivingand mating with the ribs upon the arm members. In the presentconstructiontwelve ribs and grooves are illustrated on each. Twelve isthe smallest number which will admitof placing tl1e\90 cranks at 180,120, or 60 degrees apart. By placing the cranks at the distance apartstated the shaft may be provided with two, three, four, or six cranks,which are the only numbers of cranks which at the present time areemployed in internal combustion engines.

The crank arm is formed with a pair of eyes, 5 5, one being disposedateach end. The eyesA will be formed in some suitable manner, as forinstance, by boring, and each eye is provided with a series of grooves 6and ribs 7 which are disposed parallel with the axis of the eye and theeyes are disposedin axial parallelism. The wrist pins l and the shaftends 4 are provided with ribs 8 and grooves 9 for mating with thegrooves and ribs in the crank eyes. rIhere is an opening 10 extendingfrom one side face of the arm to the other side face and extending fromone eye to the other, which opening may be a kerf disposed in the planeof the axes of said eyes. This is for the purpose of permitting theneyes to be clamped upon the ends of the members, the wrist pin or theshaft end, which are adapted to enter such eyes. A transversely disposedkey bolt seat is provided in the arm for each of the eyes and extendsthrough thearm from side to side transversely of the said kerf and cutsinto the eye. By reference to Fig. t it will be seen there isillustrated a cylindrically formed key bolt seat- 11, which at one ,endis provided with raisedv screw threads 12. This key bolt seat is forreceiving the key bolt, a form of which is illustrated in Fi s. 6 and 7.The cylindrical portion 13 o such bolt will occupy the portion v11 andits screw threaded end 14 will engage the' screw threads 12. There isprovided upon the bolt a Wrench engaging head 15 whereby the bolt willclamp the sides of the arm together and bind` the eye rmly -uponthefendl of the'wrist or shaft member as the case may be. Inassemblingthe 1parte the arm will be mounted upon the sha member orwrist pin and the key bolt seat will be drilled through the arm and insuch drilling willtake away a portion of the member which is in the eye,thus forming a key seat in such member. This is diagram-maticallyillustrated at 16 in Fig. '4. Generally in practice, the head of onebolt will be put upon one sidevof the arm and the head of the other boltvupon the other side of the arm, thus securing a perfectly balancedstructure.

In automobile and motor; boat construction it is frequently desirable tomake the crank shafts very light, and for this reason many of the partsare madetubular. The

present invention is peculiarly adapted for use in connection withtubular shafting and wrist pins. The large number, of ribs and grooves,these being located entirely around the circumference of the tubularshaft or wrist pin, will give a firm hold, even'if the grooves arecomparativelyl shallow, and when in addition to this the eye of thecrank arm is clamped or shrunk upon the member which it embraces theholding power is increased. Not only may the Yshaft ends and wrist pinsbe made tubular; but the key or clamping bolt may also be made tubularwithout reducing its eciency. It is shown tubular in Fig. 7. Y

It will be seen from the foregoing that not only is this inventionadvantageous in that it adords interchangeability of parts, not onlyadmitting ready assemblage, but also ready repair. Tt also provides. aremarkably strong, durable and lightl weight y crank shaft, one whichmay be `made of any material, as for instance from tubular stock, whichis not the case with a one piece crank shaft. Y i y f If the crankwristis made in the form shownin Fig. 9 and with the grooves of thelengt-h there illustrated and the arm is made in the size and formillustrated in Fig. 5,

-the inner ends of the grooves 9 will project into the bearing portionof the wrist pin. But by means of the construction illustrated in Figs.1,2 and 3, the grooves in the wrist pin willbe made shorter than thoseillustrated in Fig. 9 and the inner ends of the ribs upon the arm willbe cut off or beveled, as for instance by means of a reamer.. A form ofreamer 52 is illustrated in Fig. 3. By this means a close it will be hadbetween the ribs and grooves of the two members, since the ribs 7 in theeye will be beveled olf at 50 to correspond with the beveled ends 51 ofthe grooves 9 in the wrist in. This will leave a perfectly smooth caringsurface upon the crank pin between e the arms for the engagement oftheeye 17 of the connecting rod and for the intermediate bearing 19. Thecontour of the cutting-portion 53 of the reamer will correspond with thegroove ends 61. The reamer may have a guide portion 54.

A11 advantage not heretofore alluded to of the present form ofconstruction is that the eye 17 of the connecting rod 18 may be made ofone solid and integral piece. The wrist pin 1 will be placed in the eye17 and the arms 2 then applied to the wrist pin in assembling thedevice. This` is another element 4which adds to the lightness of thestructure, because a connecting rod eye so made willfof course, be muchlighter than one which is made of parts which have to be boltedtogether.-

In Fig. 12 there are illustrated in end 'view the end portion 20 of acrank shaft,

and two crank arms 21 and 22 disposed at an angle of 180 degrees one tothe other.

I ln Fig. 13 there is similarly shown a crank shaft end 30 and threearms 31, 32 and 33,

disposed atangular distances apart of 120 'f degrees. In Fig. 14 thereis shown' a shaft which is provided withcrank arms 4,1, 42, 43 and itdisposed quartcringly upon the shaft or at angular distances apart of 90degrees. This showing is merely diagrammatical and is intended toillust-rate the adaptability and interchangeability of the parts,illustrating how, by the same stock parts, a crank shaft may bevbuilt uphaving any desired number of cranks. The eye of the crank arms will allbe similar in stock articles, and the reaming of the rib ends and thedrilling of the key bolt seats may be done on each piece at the time itis used. A crank shaft vhaving one crank wrist and a pair of crank armswill take a given number of kinds of parts. To increase the number ofcrank wrists upon the shaft will not increase the number of kinds.

crank shaft having six crank wrists than to make a shaft having onecrank wrist.A

Having thus described my invention, I claim:

l. In a crank shaft, the combination with a pair of crank shaft endmembers, each having at one end a series of longitudinally disposed ribsand grooves, a series of wrist pins each havin at each end a series oflongitudinally disposed ribs and grooves,

and a series of pairs of crank arms, each arm being provided with a pairof bores disposed in axial parallelism ,and in the portion between saidbores with a kerf extending from one to the other in substan tially theplane of the axes and a pair of combined key and binding bolt seats insaidportion disposed perpendicularly to said kerfl and each opening intothe adjacent bore, each of the bores having a series of grooves and ribsmating with the' ribs and grooves on the shaft member and pins.

2. As an article of manufacture, a crank arm having a pair of eyes eachprovided with a series of grooves and ribs disposed l parallel withtheaxis of the eye, there being an opening connecting the eyes disposed inthe plane of the axes of said eyes, and a pair of transversely disposedkey bolt seats `passing through said intervening portion of the`armintersecting the said opening and cutting into the eyes.

3. As an article of manufacture, a crank arm having a pair of eyesdisposed in axial parallelism, each eye havinga series of uniformgrooves and uniform ribs disposed parallel with its axis'7 the portionof the arm between the eyes being provided with .A

a kerf connecting the eyes and disposed in about the plane oftheAsaidaxes, and a pair of combined key and binding bolt seats in saidbetween portion of the arm disposed transversely 0 opening into one ofthe eyes and the other of said seats opening into the other eye.

HORACE L. ARNOLD.

Witnesses:

JOHN FLANNIGAN, FRED. J. DOLE.'l

said kerf one of said seats I

